Electrical-test set



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E. A. JOHNSON.

ELECTRICAL TEST SET APPLlCATlON FILED APR. 22, 1919.

Patented Aug. 3, 1920.

2 SHEET SSHEET 1. v

E. A. JOHNSON;

ELECTRICAL TEST SET.

APPLICATION FILED APR. 22, L919.

L3Q8AQ- Patented Aug. 3, 19%.,

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ELECTRICAL-TEST snn Specification of Letters Patent. Patgntgd Aug; 3,192%,

Application filed April 22, 1919. Serial No. 291,974.

To all whom it may concern:

-Be it known that I, EUGENE A. JoHNsoN, a citizen of the United States,residing at Valla lValla, in the county of Walla w alla and I State ofWashington, have invented 'certain new and useful Improvements inElectrical-Test Sets, of which the following is a specification. I

My invention relates to that class of instruments used for testingelectric systems and pertains to instruments used tor measuring thepotential of electricity.

Une object 01. this invention is to provide a means whereby the voltageor amperage or electricity flowing through a certain sys tem, may beconveniently measured, the one independent of the other, whetherconstituting the charge or discharge of storage batteries, the flow toor from generators or motors, or in light systems or grounds.

A further object is, to provide improved switching mechanism and circuitarrangement whereby a suitable measuring instru- -1nent may be readilyand conveniently ap plied to electrical systems for testpurposes, andthe instrument safeguarded and'protected against a harmful current flow.

A furtherobject is to provide asystem of wiring in combination with aself contained volt meter having one or more ranges, whereby either avolt or ampere reading may be accomplished upon one instrument by asimple switching mechanism. I v j That the invention may be better understood reference is now had to the accompanying drawings, in which-Figure 1 shows the wiring diagram of the device;

Fig. 2 an end elevation of thesiX-b'laded two-throw switch andthetwo-throw safety switches; r

Fig. 3 is a plan view of the six-bladed twothroW switch and thetwo-throw safety.

switches Fig. ,4 is an elevation of the two-circuit sliding switch;

Fig. 5 is a plan view of the twocircuit sliding switch;

Fig. 6 is a plan view of the six-bladed twothrow switch with part brokenaway and showing the safety switch #5 in contact therewith. 1 p

In the drawings, A represents-the storage battery of any automobileelectric starting and lighting system, with B representing a generatorwhich supplies the battery A and the lights G with electricity. I

In testing for any trouble which may arise in the system it is obviousthat one circuit only can be tested at the sametime; therefore switchesD and E are interposed in the generator and light circuit respectivelythat these circuits maybe cut out whende sired. I r i In the instrumentimproved switching mechanisms are utilized which will now be describedas follows A two circuit sliding switch #1, Fig. 4,

consists of a lever arm 2 attachedto a shank 3, to which is attached theblades 0 and a; this shank'is insulated from the blade a and a intheusual manner, the insulation being attached to the shank andcarryingthe. said blades a and a respectively. Above the blade a and inelectrical contact therewith, is the plate 4: which is connected tothepost a A similar plate5 connects the blade a and the post a and isheldin place by. the .bolt 6. which also holds the plate 4, the twoplates being insulated .apart.

The blades a and a move in unison and connect the posts o and ,813 the:same time connecting the posts a and a respectively; the blades willalso connect the posts b and a and b and a, and also connect posts 0 andafland c and (t .,by the properm'anipulation. p

A six bladed two throw switch #2,-having in connection therewith twosafety two throw switches #4 and #5 respectively. This siX bladed twothrow switch is preferably of the design shown, although a standardswitch may be used if the necessary changes are made therein.Inthepreferred form as shown'f the blades a, etc. have projecting pieces7 to'engage electri cally with the posts a and D etc'., as desired. y w

All postson either side of the blades are designed to receive the bladessnugly, thereby making good electrical contact, with the exception ofposts d and a which are designed to have a space o'f double the width,to receive two blades before contact is made,

as follows: Post (Z will receive the blade 6 and the blade of the #4safety switch, and post a will receive the blade '0 and the blade of the#5safety switch. 7 The projecting piece 7 enters the post approximatelycentrally. This is shown in Fig. 6 where blade b is shown in post (Zwith the blade of #4. safety switch out of contact and shows thatwithout the blade of the #4: switch entering post d with the blade 6that no contact is made between them at this point; By referring to thepositionrof the switch, in Fig. 6, we note that the blades here are in,contact; blade 0 being forced against the wall of the post a by theblade of the #5 switch, which is also in firm contact with the oppositewall of this post. The two blades are electrically connected by the bar'8. A tongue 9 projects from the blades of the safety switches and theseblades are restored to their normal position out of contact by means ofthe spring 10 being released by moving the #2 switch to the right,relieving the frictiona.

resistance which holds the #4: and #5 switch blades in place duringcontact.

Different positions of the respective blades are shown by the dottedlines in Fig' 2 and will be referred to in describing the course of theelectricity through the instrument. The. polarity switch #3 is of theusual knife blade variety and needs no further description.

In'Fig. 1 #6 is a self contained volt meter having one or more rangesand is rep:

resented by broken and dotted lines rather than the conventional form,as by thisrepresentation the location of the posts of the instrument,and the three ranges shown in this case) as shown on the dial, are moreplainly represented. On the instrument is the usual indication button11.

The necessary shunts a 6 and c are conveniently located as are the fusesb and c q A single wire socket (Z is placed as a terminal of the wiringin the instrument, and from this socket a flexible cord is used toconnect into the circuitto be tested, in the drawing being shown asconnected to the battery.

y A two wire socket 12 is connected into the line and is used toaccommodate an auxiliary lead of light, flexible cord which will berequired in testing circuits at some distance from the instrument.

Testing for amperage is required for ascertaining the flow of electricalenergy through a battery during the process ofre volts during theprocess of recharge, or for testing thedrop of electrical energy duringdischarge, or for actual voltage of battery in a normal condition.

In making ampere test six blade two throw switch #2 is placed inposition G, see'Fig. 2.

7 Test A.

Test for. amperage through 300 ampere circuit asfollows:

In describing the flow of electrical energy, start at positive post ofbattery a", follow to post a through blade a of two circuit switch" #1,to post a to post a the re sistance in shunta forces a part of currentto post a 011 six blade double throw switch #2, through blade a to posta to post a", through blade a, which is insulated from blade a of twocircuit switch #1 to post a to post a, through blade a of polarityswitch #3 to post a, to post a, through blade a of switch #2 to post a,to positive post of instrument 3, through instrument to .post a, to posta, to post a, through blade G22 of switch #2 to post a to post a,through blade at of polarity switch #3, to post a, to post a, throughblade a, of switch #2 to post a, to post a to post a, to post a, throughswitch D or E respectively, through motorgenerator or light circuitshown as a anda to negative postof battery at a, completing the circuitand. giving reading o1i0 -100200- scale of instruments Test Test foramperage through 30 ampere circurrent then flows from post, (0 throughblade a of switch #lto post Z), "to 30 ampere fuse Z2 to post 5 post 6thefrcsistance in shunt b forces a partof current topost 5 through bladeZ) of switch #2, to post 6 to post .6 throughblade a of switch #1,and'then follows the rest of circuit as described in Test A, completingthe circuit and giving reading on 0 10 20 30 scale of instrument.

Test 0.

Test for amperage through amperekrircuit as follows: I

The flow of electrical energy will be the same as in test'tA, to post aThe two circuit switch #1 is now moved to post. 0 current thenfiows toposta through blade a of switch #1 to post 0 to 3 amp. fuse 0 to post c,tofpost o the resistancein shunt c forces-apart of current to posts,through blade 0 of switch #2, to post 0 to post 0", through blade aof-switch #1, and then follows the rest of circuit as described in TestA, completing the circuit and giving instrument to post (i to post (Zreading on O12-j3 scale of instrument. In making voltagetests the sixblade two throw switch #2 is placed in the position H, see-Fig. 2. lVewill now describe the voltage test through the 30 volt circuit. 4 o

Beginning at the positive post a of the battery, thecourse of thecurrent flow will I be to post a bladegai of two circuit switch #1, posta post a through shunt a, post a, post a, post a ",-post a, throughblade a of switch #2, to post (Z to post a, to post a fl to post 6Zthrough blade a of switch #3, to post a, to post a, to post (Z throughblade a of switch #2, to post a, positive post or instrument a, throughFrom this course a branch lead is run to-safety switches #4: and #5respectively, from the point E and will be hereinafter explained. Thencethrough blade at of switch #2, to post a to post a through blade a ofswitch #1, to post a ,'to post a, through blade a, to post d, to post a,to post 60 through blade a -ot switch- #2, to post 6V, to post (Z tonegative post of battery a.

lVe' will now describe the voltage test through the 3 volt circuit.

Beginning at the positive post 00 of the battery, the course of thecurrent flow will be to post (0 through blade at of switch #1, to post 6to fuse 6 to post If, to post 6", to shunt If, to post a, to post at, topost (L29, through blade a of switch #2, to post (P, to post a to posta, to post d through blade of switch #3, to'post a to post a, to post (Zthrough blade (5 of switch #2, to post a, to positive post of instrumenta, through instrument to post (P, to post D through blade 6 of switch#2, to post 6 to post I), to post a, to post a, through blade (Z13 ofswitch #3, to post cl, to post a, to post 64 throughblade a of switch#2, to post 61 to post elf, to negative ost battery a. V d

On 0.1' volt circuit. Beginning at positive post of battery a", post cthrough blade a ot' switch #1, post 0 to fuse 0 to post 0 to post 0shunt 0 to post a to post a, through to to to blade a of switch #2, topost (Z to post a, to post a, to post (Z through blade o of switch #3,to post o to post a, to post (Z through blade (1. of switch #2, to post(1., to positive post of instrument 01 through instrument a, to post a,through blade 0 of switch #2, to post 0 to post 0 to post a, to post a,through blade a of switch #3, to post (1, to post a, to post a, throughblade a or" switch #2, to post (F, to post (Z tonegative post ofbatterya.

A, branch lead leaves the line at E and connects with switch posts 'Eand E of safety switches #4.- -and-#'5 respectively;- a circuit is thuscomplete through the safety switches #42 and #5, and with the blades inthe positionl, Fig. 2, through the 30 volt range of the instrumentregardless of the position of two circuitslidin'g'switch #1. Bythismeans the instrument is protected from I a higher range currentpassing through a lower range circuit 'o'fthe instrument,'and-thus areading'may beobtained on the 2-30 volt graduations, but should a finerreading be wanted on the finer graduations of the instrument theswitches #4 or #5, asthe case may be, must be thrown to position J. 1This instrument is equally applicable for use with an instrument havingagreateror a plurality of resistances interposed in said circuit, aswitch forincluding any one of the resistances in the circuit andexcluding the others, and a switch mechanism for connecting the selectedresistance in parallel with the instrument when in one position, and inseries with the instrument when in another position. i i p p 3. In anelectrical test set, a current measuring instrument, a plurality. ofresistances of diiierent ranges having circuit connections withtheinstrument, a switch for including any one of the resistances in thecircuit of the instrument and for eX- cluding the others, a switchmechanism having means for connecting the selected resistance inparallel and in series with the instrument, branch circuits normally.connecting the circuits of the resistances of a lower range with thecircuit of the.resistance of higher range, and switches controlling thebranch circuits;

4.111 an electrical test set, a current measuring instrument, aplurality of resistances of different ranges having circuit connectionswith the instrument,a switch for including. any one of the resistancesin the circuit of the instrument and for eX- cluding the others, aswitch mechanism having means for connecting the selected resistance inparallel and in series with the instrument, branch circuits connected tothe circuit of the resistance of higher range, and a switch mechanismhaving means for normally connecting the branch circuits to theresistances of lower'range and for disconnecting the same.

5. In an electrical test, set, a current measuring instrument, aplurality of resistances of diflerent ranges having circuit connectionswith the instrument, a switch for including any one of the resistancesin the circuit of the instrument and for eX- cluding the others, aswitch mechanism having means for connecting the selected resistance inparallel and in series with the instrument, branch circuits connected tothe circuit of the resistance of higher range, anda switch mechanismhaving means for normally connecting the branch circuits to theresistances of lower range and for disconnecting the same, the aforesaidswitch means which connect the selected resistances of lower range inseries with the instrument having an electrical connection with thelast-mentioned switch mechanism when the branch circuits aredisconnected, to complete the connection of the selected resistances oflower range in series with the instrument. 1

6. In an electrical test set, a current measuring instrument, aplurality of resistances of diiferent ranges having circuit connectionswith the instrument, a switch for including any one of the resistancesin the circuit of the instrument and for excluding the others, aplurality of switch blades, a pair of contacts for each blade,

contacts, and electrically connected to the first-mentioned bladescontrolling the circuits of the resistances of lower range, the switchblades of the branch circuits being disengageable from the contacts ofthe latter, and engageable with the first-mentioned blades to completethe circuit connections of the resistances of lower range.

In testimony whereof I afiix my signature.

EUGENE A. JOHNSON.

